tmpnam() : permission denied when try to open temp file

Hey folks!

Code:

char tempname[FILENAMELENGTH];
FILE *p_openfile1;

tmpnam(tempname);
printf("%s", tempname);

if((p_openfile1 = fopen(tempname, "w")) == NULL) {
    perror("Error opening temp file"); 
    exit(EXIT_FAILURE);
}

When I try to open the filename for writing, the error message is:

Code:

\s2vc. Error opening temp file: Permission denied

I have no problems opening any other file, just the temp file generated by tmpnam().

I am assuming that fopen() tries to open the file in the "Windows" folder, which I don't have permission to do as a normal user. Does the fact that the temp filenames ends in a . have anything to do with the problem of opening it?

EDIT: Actually, is \ a part of the filename too? Could that be causing problems?

My textbook doesn't mention any such problem.

Thanks in advance.

Look at the filename -- it starts with backslash. Looks like something is funny with your system so that it's not using the actual Windows temp directory.

Most manuals for tmpnam() say very clearly "Do not use this function."

Thanks brewbuck.

In my textbook, the output[EDIT: printed in the book itself, not on my system] of a similar piece of sample code also has a \ in the temp filename that is generated.

Perhaps this is a problem with tmpnam() and Windows systems in general.

I'll try another function!

EDIT: A quick search on google seem to indicate that only tmpnam is ANSi compatible for generating temp files(text). :/

tmpfile() is also standard. It gives you an open FILE. If you don't explicitly need the filename, just an open temporary file, that should work.